package hao.d02;

 class Test1 {

}
class Sub extends Test1 {
    public String getFields() {
        String name = "Sub";
        return name;
    }
}

class DoSub {
    public static void main(String[] args) {
        Test1 b = new Sub();
        System.out.println(((Sub)b).getFields());// 插入语句处//向下转型！！
    }}
